This invention relates to a paper money discriminating method and an apparatus therefor, and more particularly to a method and an apparatus for discriminating between genuine and counterfeit, or suspect paper money (such as dollar bills) printed in magnetic ink.
Techniques heretofore proposed for discriminating between truth and falsehood of paper money include, for example, a means to check a depicted pattern in a particular print portion of a bill by using a photoelectric sensor or the like to detect light and shade of that portion, and a means to check the type of printing ink (i.e. magnetic ink or not) by using a magnetism detecting sensor or the like to find out whether magnetism is present in a particular print portion of a bill.
However, the above conventional techniques have the following disadvantages.
The first mentioned means to check a depicted pattern optically has various inconveniences owing to the recent progress of printing technique which has made it difficult to discriminate between genuine and counterfeit, or suspect paper money only by a depicted pattern. That is to say, checking into details of the pattern would not only complicate the operation but also require an extended time for forming a judgment and would increase chances of operational errors. On the other hand, the latter means to determine the type of printing ink by presence or absence of magnetism is incapable of accurate discrimination between true money and false money where the false money is simply impressed, coated or adhered with a magnetic material, since this means consists only of checking to find out if the bill contains magnetism.